Global Population Reduction: Confronting the Inevitable

Global
Population Reduction: Confronting the Inevitable

Looking
past the near-term concerns that have plagued population policy at the
political level, it is increasingly apparent that the long-term sustainability
of civilization will require not just a leveling-off of human numbers as
projected over the coming half-century, but a colossal reduction in both
population and consumption.

It has
become increasingly apparent over the past half-century that there is a growing
tension between two seemingly irreconcilable trends. On one hand, moderate to
conservative demographic projections indicate that global human numbers will
almost certainly reach 9 billion, perhaps more, by mid-21st century. On the
other, prudent and increasingly reliable scientific estimates suggest that the
Earth's long-term sustainable human carrying capacity, at what might be defined
as an "adequate" to "moderately comfortable" developed-world standard of
living, may not be much greater than 2 to 3 billion. It may be considerably
less, particularly if the normative lifestyle (level of consumption) aspired to
is anywhere close to that of the United States.

As a consequence of this modern-day
"Malthusian dilemma," it is past time to think boldly about the midrange future
and to consider alternatives that go beyond merely slowing or stopping the
growth of global population. The human species must develop and quickly
implement a well-conceived, clearly articulated, flexible, equitable, and
internationally coordinated program focused on bringing about a very significant reduction in human numbers over the
next two or more centuries. This effort will likely require a global population
shrinkage of at least two-thirds to three-fourths, from a probable mid-to-late
21st century peak in the 9 to 10 billion range to a future (23rd
century and beyond) "population optimum" of not more than 2 to 3 billion.

Obviously, a demographic change of
this magnitude will require a major reorientation of human thought, values,
expectations, and lifestyles. There is no guarantee that such a program will be
successful. But if humanity fails in this effort, nature will almost certainly
impose an even harsher reality. As a practicing physical anthropologist and
human evolutionary biologist, I am concerned that this rapidly metastasizing
(yet still partly hidden) demographic and environmental crisis could emerge as
the greatest evolutionary/ecological "bottleneck" that our species has yet
encountered.

Although the need for population
reduction is controversial, it can be tested scientifically. The hypothesis may
be falsified if it can clearly be shown that ongoing estimates of global
population size over the next few hundred years will not exceed our increasingly
accurate projections of both current and future optimal carrying capacities.
However, the hypothesis will be confirmed if future global population size
continues to exceed those carrying capacity estimates by a significant margin.
And even if the 2 to 3 billion optimal carrying capacity estimate turns out to
be off by, say, a factor of two, achieving a global population optimum of 4 to
6 billion would still necessitate a very substantial reduction from the 9-plus
billion projected for mid-century.

Below the Radar?

It is
surprising how little scientific and public attention has been directed toward
establishing quantifiable, testable, and socioculturally agreed-upon parameters
for what the Earth's long-term human carrying capacity might actually be.
Unfortunately, with only a few notable exceptions, many otherwise
well-qualified scientific investigators and public policy analysts have been
rather hesitant to take a clear and forthright position on this profoundly
important matter. One wonders why-inherent caution, concerns about professional
reputation, the increasingly specialized structure of both the scientific and
political enterprises, or any of several other reasons. Given the issue's
global nature and ramifications, perhaps the chief reason is simply "scale
paralysis," that enervating sense of individual and collective powerlessness
when confronted by problems whose magnitude seems overwhelming.

Certainly the rough-and-ready human
carrying capacity estimates of the more distant past show considerable
variation, ranging from fewer than 1 billion to over 20 billion. And it is
obvious that it will be difficult to engender any sort of effective response to
the crisis if the desired future population goals continue to be poorly
understood and imperfectly articulated. It is, however, worthy of note that
several investigators and organizations have developed reasonably well thought
out positions on future global population optima, and those estimates have all
clustered in the range of 1 to 3 billion.

I hope my hypothesis is wrong and
that various demographic optimists are correct in claiming that human numbers
will begin to stabilize and decline somewhat sooner than expected. But this
optimism is warranted only by corroborative data, that is, only if the
above-mentioned "irreconcilable numbers" show unmistakable evidence of coming
into much closer congruence.

Clearly, assertions that the Earth
might be able to support a population of 10, 15, or even 20 billion people for
an indefinite period of time at a standard of living superior to the present
are not only cruelly misleading but almost certainly false. Notwithstanding our
current addiction to continued and uninterrupted economic growth, humanity must
recognize that there are finite physical,
biological, and ecological limits to the Earth's long-term
sustainable carrying capacity. And to judge by the growing concerns about
maintaining the quality, stability, and/or sustainability of the Earth's
atmosphere, water, forests, croplands, fisheries, and so on, there is little if
any doubt that many of these limits will soon be reached, if they haven't
already been surpassed. Since at some point the damage stemming from the
mutually reinforcing effects of excessive human reproduction and
overconsumption of resources could well become irreversible, and because there
is only one Earth with which to experiment, it would undoubtedly be better for
our species to err on the side of prudence, exercising wherever possible a
cautious and careful stewardship.

Perhaps it is time that the burden
of proof on these matters, so long shouldered by so-called neo-Malthusian
pessimists, be shifted to the "cornucopian optimists." Let them answer: What is
the evidence that the Earth can withstand, without irreparable damage, another
two or more centuries during which global human numbers and per-capita
consumption increasingly exceed the Earth's optimal (sustainable) carrying
capacity?

In any event, having established a
"quantifiable and falsifiable" frame of reference, it is time to make the case
that current rhetoric about "slowing the growth of" or even "stabilizing"
global human numbers is clearly insufficient. Both the empirical data and
inexorable logic suggest that our default position for the next two or three
centuries ought to seek a very significant reduction in global human numbers.

Acknowledging Our Dilemma

Is it naive
to hope that, once a critical mass of concerned investigators begins to make a
serious case for such a reduction, it would become much easier for scientists,
environmentalists, politicians, economists, moralists, and other concerned
citizens of the planet to speak forthrightly about humanity's critical need for
population stabilization and shrinkage? At the least, they should not feel as
though they are committing political, professional, or moral suicide by raising
these issues. Time is increasingly precious, and our window of opportunity for
effective remedial action may not be open much longer-assuming it has not
already closed.

Until demonstrated otherwise, I
would therefore argue that insufficiently restrained population growth should
be considered the single most important feature in a complex (and synergistic)
physical, ecological, biocultural, and sociopolitical landscape. Regulating
human population size, and confronting the numerous problems that will be
engendered by its eventual and inevitable contraction, should thus be accorded
a central position within the modern dilemma, and as such should be dealt with
much more forthrightly, and promptly, than has heretofore been the case.

More than half a century ago, at
the dawn of the nuclear age, Albert Einstein suggested that we would require a
new manner of thinking if humankind were to survive. Even though the population
explosion is neither as instantaneous nor as spectacular as its nuclear
counterpart, the ultimate consequences may be just as real (and potentially
just as devastating) as the so-called nuclear winter scenarios promulgated in
the early 1980s.

That there will be a large-scale
reduction in global human numbers over the next two or three centuries appears
to be inevitable. The primary issue seems to be whether this process will be
under conscious human control and (hopefully) relatively benign, or whether it
will turn out to be unpredictably chaotic and (perhaps) catastrophic. We must
begin our new manner of thinking about this critically important global issue
now, so that Einstein's prescient and legitimate concerns about human and
civilizational survival into the 21st century and beyond may be addressed as
rapidly, fully, and humanely as possible.

Don't
speak to me of shortage. My world is vast

And
has more than enough-for no more than enough.

There
is a shortage of nothing, save will and wisdom;

But
there is a longage of people.

-Garrett Hardin (1975)

Ken Smail is a professor in the Department of Anthropology at Kenyon
College, and the author of several papers and essays on population that have
appeared in Population and Environment,
Politics and the Life Sciences, and
other journals. This essay is dedicated to the memory of Kenneth Boulding and
Garrett Hardin.

References
and readings for each article are available at www.worldwatch.org/pubs/mag/.